# Alleghany Corporation

**Canonical:** https://apis.io/providers/alleghany/  
**Website:** https://www.alleghany.com  
**APIs profiled:** 0

Alleghany Corporation is a holding company engaged in property and casualty reinsurance and insurance through its subsidiaries, with additional investments in non-financial businesses held via Alleghany Capital. Founded in 1929 by railroad entrepreneurs Oris and Mantis Van Sweringen, the company transitioned over decades from rail holdings into specialty insurance and reinsurance, and is headquartered at One Rockefeller Plaza in New York City. Its principal insurance subsidiaries are Transatlantic Reinsurance Company (TransRe), a global reinsurer founded in 1977 with roughly 600 employees across 23 offices and more than $40 billion in claims paid to date; RSUI Group, a wholesale excess and surplus (E&S) underwriter spanning Property, Casualty, Professional Liability, Management Liability, and Binding Authority lines; and CapSpecialty, a specialty casualty and surety underwriter. Alleghany Capital holds non-insurance operating companies including toy and collectibles maker Jazwares (Squishmallows, Pokémon, Roblox, Fortnite licensed lines). On March 21, 2022, Berkshire Hathaway announced an $11.6 billion all-cash acquisition of Alleghany at $848.02 per share, which closed in October 2022. Alleghany now operates as a wholly-owned subsidiary of Berkshire Hathaway, contributing approximately $8.8 billion in 2025 gross premiums written and roughly $14 billion in insurance float to the parent. As a holding company whose operating units distribute exclusively through reinsurance intermediaries, wholesale brokers, and independent agents, Alleghany and its subsidiaries do not publish a developer portal, OpenAPI specifications, SDKs, or any other machine-readable API artifacts; the only digital surfaces exposed publicly are gated broker and agent login portals.

## Kin Score — 3.0 / 100 (minimal)

Scored 2026-08-21 under rubric 0.12.0. Trend: flat (+0.0 from 3.0).

| Facet | Score |
|---|---|
| Discoverability | 50.0 |
| Contract Quality | 0.0 |
| Governance | 0.0 |
| Contract Governance | 0.0 |
| Operational Transparency | 5.3 |
| Developer Ergonomics | 0.0 |
| Commercial Clarity | 0.0 |
| Access Clarity | 0.0 |

Regulatory layer — **Insurance**: 9.1 (matched via tags).

## Agent readiness — 0.0 (human-only)

| Dimension | Value |
|---|---|
| Spec Presence | no |
| Agentic Access | no |
| Reversibility Documented | no |
| MCP Server | no |
| Auth Clarity | no |
| Idempotency | no |
| Error Semantics | no |
| OpenAPI Examples | no |
| Rate Limit Signal | no |
| Event Surface Described | no |
| Agent Skills | no |
| Well Known Catalog | no |
| Consent Identity | no |
| Agent Card | no |
| Dry Run Mode | no |

## Access

Unknown — onboarding: unknown, pricing: unknown, trial: no (confidence: low).

## Security (1)

- **Alleghany Domain Security** — TLSv1.3 · HSTS · DMARC

## Tags

Insurance, Reinsurance, Property and Casualty, Specialty Insurance, Excess and Surplus, Surety, Financial-Services, Holding Company, Berkshire Hathaway Subsidiary, Toys And Collectibles, Fortune 500

---

Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/providers/alleghany/). Scores are computed from the provider's own public artifacts under a published rubric.